Known methods for measuring a component or characteristic in a liquid sample, for example the blood sugar level in a blood or urine sample, involve the use of a test strip having a measurement portion to which is to be applied the liquid sample to be tested. In use, the test strip is held at its tip and brought into contact with the liquid sample.
In the case of test strips that are designed to measure the level of sugar in an individual's blood, a needle is used to pierce or prick the individual's finger to thereby draw a blood sample. The test strip is then pressed onto the finger to cause the test strip to absorb a sample of blood. However, this method of obtaining a blood sample on a test strip can be somewhat problematic. Because this technique requires significant human involvement and typically only results in a small sample of blood for purposes of analysis, it sometimes happens that the blood sample is not accurately applied to the measurement portion of the test strip.
U.S. Pat. No. 5,100,620 discloses what is referred to as a capillary tube reagent format device that is designed to collect a sample of blood which is absorbed by a test strip that is mounted on the device. The device includes a transparent body having a hole extending between opposite ends of the body. The test strip is mounted on a shoulder encircling one end of body to form a flow passageway between the test strip and the body. A vent passageway is formed in the body and communicates the flow passageway with the atmosphere. During use, the tip of the body is brought into contact with a sample of blood, with the blood being drawn up through the hole in the body by capillary action and flowing into the flow passageway. As the blood flows through the hole in the body and into the flow passageway, air in the hole and the flow passageway is vented through the vent passageway. As the blood flows into the flow passageway, it is absorbed by the test strip. Thereafter, the device is mounted on a reader for determining a characteristic of the blood sample (e.g., blood sugar level).
This known capillary tube reagent format device is susceptible of certain disadvantages and drawbacks. In one respect, the device requires that the body be formed with a vent passageway. This means that the mold used to form the body must be appropriately designed to produce the vent passageway which increases the cost and complexity of the mold, particularly in light of the fact that the vent passageway must be quite small in size to avoid what the patent refers to as undue evaporative cooling. In addition, the configuration of the tip end of the device may make it difficult to effect a smooth flow of blood into the hole in the body. Also, when the device is mounted on a reader to determine the desired characteristics of the collected sample on the test strip, the reader may become soiled or contaminated by the liquid sample on the test strip. Further, the configuration of the test strip is not well suited to facilitating absorption of the blood sample.